Starting with 100% state of charge in the morning, our normal daily use is about 90 amps. That's without even thinking about power conservation. Cooking with a microwave, making coffee, watching television for 2 or 3 hours in the evening, etc.
Our van is designed with a door to close off the sleeping area where the AC unit and the thermostat are, so we're actually only cooling half of the van when we sleep. Because of that arrangement, the AC only draws about 70 amps per hour since the compressor cycles off more than usual. (It's 90 amps with the compressor on.) The inverter and phantom loads are another 5 or so, which leaves about 120-140 amps for charging when the AC is running and the alternators are combined.
With a full battery at bedtime, our auto-start system is set to start the engine when the state of charge drops to 20%. That usually takes about 5.5 to 6 hours. Then while we're still asleep the engine runs for one hour (maximum auto-start system time) which delivers another 120 amps to the battery (the AC is still cooling). Then we get another 1.5 hours or so on battery alone, which gets us our 8 hours of sleep. We wake up with enough power for breakfast and coffee, then we have to either drive or idle to recharge. Takes about 2.5 hours to get back up to 100% SOC from 20% at idle with no loads.
So our worst case power usage is about 730 amps per day while boondocking in the Texas summer, idling the engine about 4.5 hours per day (burns about 2 gallons of gas). The rest of the year it's about 90 amps of use and less than an hour of idle time. In practice, when it's cool enough to sleep without the AC we could boondock for 5 days without running the engine. But we rarely stay anywhere more than two nights.
Would you be able to clarify which numbers are amps and which are amp hours, it is quite confusing, I fear. :thanx: